You gather a massive amount of electric energy into a 5 foot-diameter orb, which can then move to your mental instructions and attack your enemies. The ball lightning may be made to move a total of 10 feet per two caster levels each round, during which it deals 1d6 points of electricity damage per caster level (max 25d6) to any creature or object that it crosses paths with. Creatures entering the square that the ball lightning is in or starting their turn in the same square as the ball lightning are likewise dealt damage. Ball lightning is not a creature and is therefore immune to attacks, and cannot be physically or mentally influenced other than by the caster.

In the round of casting the spell, you determine the location in which the ball lightning comes into existence, and may immediately direct it to move its allotted distance for the round. If you willfully stop concentrating upon the spell, the ball lightning will cease its motion and disappear next round.